Sorption of liquids by wool. Part IV. Sorption of ethanol by modified wool

Experimental results for the sorption of liquid ethanol by a variety of modified wools are described. Even slight changes in the chemical and physical structure of wool produced large changes in ethanol sorption rate. Blocking of amino groups decreased the sorption rate due to removal of primary sorption sites, but, surprisingly, carboxyl group modification greatly increased the rate. Modification of disulfide crosslinks increased the rate, while in most cases surface modification decreased it, which is contrary to expectation if a surface barrier to diffusion of penetrants is assumed. Theories are advanced for the observed changes in sorption properties and for the small changes found when water if used as sorbate. Saturation sorption values showed only slight changes from that for untreated wool. The largest increases resulted from disulfide bond modification, which is explained as due to lower resistance of the treated wool to swelling forces, allowing greater swelling and sorption.